Charcoal-kiln



\ (Nb Modem H. M. PIERCE.

CHARCOAL KILN.

9 Patentedeb. 0.1883.

m MW@ '-Q I m S A "D .M `A W@ N. PETERS. Plwbuxmgnpher. wnshinglun. D.C.

PATENT 1 Fries.

HENRY M. PIERCE, 0E cHIoAGo, ILntNos.

CHARCOAL-KILN.

SPECIFICATION forming` part of Letters Patent No. 272,76dated February20, 1883.

` Application tiled November, 1882. (No model.)

To all whom t't may concern Be it known that I, HENRY M. PIERCE, acitizen of the United States, residing at Ohicago, in the county of Cookand State of Illinois, have invented certain new land usefullmprovements in Charcoal-Kilns and in the Manufacture ofOharcoal and Ihereby declare the following to be a full, clear, and exact descriptionot' the same, reference being had to the accompanying drawing, whereinis shown a longitudinal vertical section of a kiln and accessoriesembodying my invention.

The object ot' this invention is to increase the yield of charcoal, inquantity, weight, and measure, per cord of wood, by improvements in kilnor oven construction and improvements in the method of generating andapplying heat-for the reduction'of wood to charcoal. To accomplish thisit is necessary to avoid certain very objectionable features in charcoalkilns as now constructed, and. to changethepresentmethod ot'reducingthewood in such kilns to charcoal. i

Charcoal-kilns as now ordinarily constructed are either round or oblong,though sometimes rectangular kilns are used. The round are eitherstrictly conical and taper to a point or have an ovalv or flattenedroof. The former presents the appearance of a cone, the latter of afrustum ofa cone. The oblong kilns have perpendicular walls, archedroofs, and square corners, and are sustained by upright posts that areproperly braced at the lower ends and at the upper ends are tied acrossthe top of the kiln. The objectionable feature is not so much in theform as in the height made necessary to give adequate capacity to thekiln.

It is well known that up to acertain extent better and moreeconomicalresults follow from charring wood in large quantities. Toaccomplish this, especially in the case ofround kilns, the excessiveheight amounts to a necessity. The same error is largely necessitated inthe present method of constructing oblong kilns.

In the operation of these kilns the charring process continues rapidlyuntil from one-halt or two-thirds of the contents of the kiln has beenreduced to charcoal. This is always the upper one-halt' or two-thirds.At this point, owing to the heat hanging in the upper part of the kiln,further carbonization is greatly retarded. The result is that it takeslonger to char the one-third of the charge in the lower part of the kilnthan the two-thirds in the upper part'. In reducing this lower part ofthe charge to charcoal so great is the loss in wood and time thatthecollier often prefers to ar- 'rest the operation and leave a largepart ofthe kiln contents uncharred or in the form of brands. In a kilnholding eighty cords ot' wood the uncharred portion and brandsordinarily aggregate twenty per cent. of the entire charge.

In the present4 method of making charcoal in kilns it is the commoncustom to generate the heat necessary to carbonization by ring the woodin the kiln itself. It is apparent that to make sufiicient heat to carryon this process in large receptacles a considerable portion of the wooditself and also of the valuable wood-gases is actually consumed anddestroyed.

To avoid the lirst. objectionable featurenamely, error in kilnconstruction- I buildmy kilns low, with square corners, with as flat anarch as possible, and of unusual length. The great length is necessaryto obtain the requisite capacity. Furthermore, in order to hold the heatnear the bottom while traversing the kiln I introduce one or morependent partitions extending from the roof ofthe kiln downward to agreater or less distance from the bottom. I have doors for charging andemptying the kiln in the sides of the kiln, between the partitions,instead of the ends of the kiln. In place of perforating the sides ofthe kiln with holes, as.is,customary, for the escape of the volatilegases thrown oltin process of carbonization, l build one or-more-chimneys outside kiln is made with brick grouted with cement andinclined to one or more gutters running across the kiln.

To avoid the second objectionable feature arising from internal tiring,l construct in comhina-tion with the kiln herein described an out- IOO -side heat-generating furnace and connect yit with the kiln by a suitableiue. In this furnace I burn fuel that cannot be used for makingcharcoal, such as edgings, sawdust, tanbark, the refuse of a wood-yard,gases, atomized tar, &c.

I will now specifically describe the kiln as illustrated in thedrawings.

A indicates the kiln, which is a low rectangular chamber provided withan arch or crown, a, as nearly flat as the same can be made consistentwith strength and security. This chamberis of unusual length-#forpurposeofdescription, say, twice the length of an ordinary rectangularkiln-and its upper portion is divided up by transverse pendent walls a',which divide up the charge of the kiln and canse the descent into theline of draft of all gases and vapors which would otherwise accumulatein the upper portion of the kiln. The special value of this feature willbe apparent when it is remembered that the charge sinks down ascarbonization advances, and unless the kiln were so divided up a largechamber would result, in which a great volume of heated vapors and gasescould accumulate at a point out of the line of draft, whereas thedivision-walls cause such heated gases to dip and circulate throughevery portion of. the charge.

In the side walls ot' kiln A, at points between thepartitions,arecharging-doors B,and,if desired, other charging-doors, b,may be made in the upper part of the kiln. These doors are closed andluted when the kiln is charged, and with these exceptions there are noopenings into the kiln except the induction and eduction flues,hereinafter referred to.

At one end of the kiln A, I erect one or more furnaces or irechambers,F, with suitable stacks, S, and .dampers N, and connect said furnaces,by a flue or llues, T, provided with dampers N', with the kiln A at ornear its base. In these furnaces any suitable class of fuel which willgenerate heated gases may be employed. At or near the opposite end ofthe kiln A, I erect one or more stacks, C, and connect the same with thekiln by a liuc or ilues. c, guarded by dampers N with the base of thekiln. It will be seen that the draft is substantially along the bottomof the kiln, and the highly-heated vapors and gases which are evolvedfrom the charge in the kiln, though they may first rise in the separatecompartments, must eventually, owing to their own pressure and thenatural draft, descend and move toward the stack or stacks, which keepthe heat near the bottom of the kiln. The bottom of the kiln ispreferably made up of a series of transverse inclines, the highestpoints of which are opposite the charging-doors B and the lowest pointsbeneath the pendent transverse partitions ct', thus forming gutters G,which will collect any liquids which may condense on the pendentpartitions and prevent its escape by the doors, if the same areinsufciently secured. Traps t may be provided opposite the gutters G,for preventing the accumulation of liquid and for recovering andutilizing any valuable products. The stack orstacks C may be connectedwith a condenser, and the gas and vapor maybe conducted from the kiln bya fan or other exhaust and utilized, it' desired.

The operation of this improved kiln, in combination with the outerheatgenerating furnace, is as follows: The kiln A is first charged withwood. Then the doors B B are shut and luted up and the kiln hermeticallysealed. The furnace F, in connection with the kiln A, is then heated toa high temperature. During the preparation of this furnace the productsof its combustion escape through stack S, and the air is regulated so asto make the combustion ot' the fuel in this furnace, as far as possible,complete. The damper N at foot of stack S is then closed and the damperN of the flue T, communicating directly with the interior of the kiln,opened. The hot non -combustible gases from the furnace fill the kilnand rapidly bring it to a temperature necessary to carbonization. Thegases issuing from the outer furnace, after communicating their heat tothe contents of the kiln, mix with the gases evolved by thecarbonization of the wood and find ontlet through the chimneys C. No airbeing admitted to the kiln Aand no air passing through the furnace Funconsurned, the carbonizing process continues from beginning to endwithout burning any wood or valuable gases. In'vv the case of onefurnace being employed and connected with one end of this oblong kiln,the chimney or gas-exits are placed near or at the opposite end. Thusthe heated products of the outer furnace, together with the hot volatilegases evolved in the process of carbonizationhtraverse the entire lengthof the kiln.

In cases where a furnace is used at each end of the kiln, and both areoperated at the same time, the chimney or chimneys for the removal ofthe volatile products of distillation are placed near the center of thekiln.

During the charring operation the partitions a' a compel the heatedgases to dip toward the lower parts of the kiln, instead of ruimingalong its roof.

The actual results of the operation are--n First. A positive increase ofthe quantity and quality of the charcoal per cord. This charcoal is lessporous, heavier, and will carry a heavier burden in a blast-furnace thanchar coal produced in any other way.

Secondly. A large increase in the valuable volatile wood products isobtained, as none of them have been burned in the process ofcarbonization.

This Akiln A maybe operated in the ordinary way by not using the outerfurnace, F, but by internal tiring and admission ot' air through holesin the bottom of the kiln.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, 1s-

1. A charcoal-kiln having one or more trans- IOO IIO

verse pendent partitions which divide the upper portion of the kiln intoa series of separate chain bers, substantiall y as and for the purposespecified.

2. A charcoal-kiln having one or more transverse pendent partitionswhich divide the upper portion of the kiln into a series of separatechambers, and having its floor made np of inclines Whose lowest pointsare beneath the transverse pendent partitions, substantially as and forthe purpose specified.

3. The combination, with a kiln having one or more pendent partitionswhich divide the upper portion of the kiln into separate charnbers, ofan independent furnace or fire-chamber and a stack, both of which areconnected

